The role of GPC5 in lung metastasis of salivary adenoid cystic carcinoma.

Abstract Objective Proteoglycans play a crucial role in salivary adenoid cystic carcinoma (SACC) tumorigenesis, neurotropic growth and lung metastasis. In this study, we investigated the role of GPC5 in the lung metastasis of SACC. Design The expression of heparan sulfate proteoglycans (HSPGs) was detected in SACC-M (high lung-metastatic cell line), SACC-2 (low lung-metastatic cell line) and SACC-83 (low lung-metastatic cell line) cells by relative quantitative Real-Time PCR. The expression of GPC5 was detected by immunofluorescence and Western blot analysis in SACC-M, SACC-2 and SACC-83 cells, and by immunohistochemical analysis in primary tumours from 16 cases of SACC patients with or without lung metastasis. GPC5 expression was silenced in SACC-M cells, cell proliferation and tumour growth was evaluated by MTT assay and nude mice model, respectively. Results Expression of most HSPGs was decreased in SACC-M cells, but GPC5 expression increased 3.24-fold and 815.69-fold (more than 3-fold) in SACC-M compared with SACC-2 and SACC-83 cells, respectively. Immunohistochemical analysis showed higher expression of GPC5 in SACC with lung metastasis compared to SACC without lung metastasis. The lung metastasis of SACC-M cells in nude mice was obviously decreased after GPC5 silencing ( P Conclusion GPC5 may contribute to lung metastasis of SACC.